of medford



A. B. SHAW.

INNER TUBE.

APPLICATION FILED 050.4.1919.

Patented Nov. 30, 1920.

UNITED STATES PATENT OFFICE.

AI B. SHAW, OF MEDFORD, MASSACHUSETTS, AS-SIGNOR TO SHAW TIRE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

INNER TUBE.

Patented Nov. 30, 1920.

Application filed December 4, 1919. Serial No. 343,085.

To all whom it may concern:

Be it known that 1, Ar B. SHAW, a citizen of the United States of America, and a resident of Medford, in the county'of Middlesex and Commonwealth of Massachusetts, have invented certain new and useful. improvements in Inner Tubes, of which the following is a specification.

This invention relates to inner tubes for tires and has for its object the production of a tube which will retain air under pres sure even after the tube has been punctured. Y s

The present invention is an improvement upon the invention shown and described in U. S. Letters Patent No. 1,242,252 issued to me Oct. 9, 1917. V

The invention consists of a tube molded with a plurality of inwardly extending cupshaped members which are substantially fixed when the tube is deflated but which are adapted to be forced outwardly against the inner face of the shoe when the tube is inflated thereby causing the material of said tube to be compressed sidewise in every direction, each of said cup-shaped members having a plurality of concaved depressions in the side wall thereof in order that amore perfect and equalized compression of the material'may be obtained.

The invention further consists in certain novel features of construction and arrangement of parts which will be fully understood by reference to the description of the drawings and to the claims to be hereinafter given.

For the purpose of illustrating the in vention, one preferred form thereof is illustrated in the drawings, this form having been found to give satisfactory and reliable results although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized and the invention is not limited to the precise arrangement and organization of these instrumentalities as herein shown and described, except as required by the scope of the appended claims.

Of the drawings: V

Figure 1 represents an elevation of an inner tube for automobile tires.

Fig. 2 represents a transverse section of a tire having confined therein an inner tube embodying the principles. of the present invention, said tube being deflated.

Fig. 3 represents a similar section with the tube inflated.

Fig. i represents a plan of a portion of said inner tube.

Fig. 5 represents a section of the same on line 5, 5, on Fig. 4, and

Fig. 6 represents a section of the same on line 6, 6, on Fig. 4.

Similar characters indicate like parts throughout the'several figures of the drawings.

In the drawings, 10 represents an inner tube of usual construction before it has been tending cup-shaped members 11 formed therein, these cup-shaped members being substantially fixed when the inner tube is deflated.

Preferably, the cup-shaped members 11 are so constructed that they intersect each other on the lines 12 and the walls of the members 11 on these lines are each slightly concaved as indicated at 13 on Figs. 2 and 5 of the drawings.

The cup-shaped members 11 may be formed with three or more sides 12, but preferably are formed with six sides as shown in Fig. 4c of the drawings.

The central row of cup-shaped members 11 are-all of the'same size and'those on either side of this central row of cup-shaped members decrease in size, as shown in Fig. i of the drawings. in order to conform to the shape of the entire inner tube 10.

In other words, the outer periphery of the inner tube 10 is of greater diameter than the inner wall thereof and insomuch as it is necessary that there should be as many cupshaped members 11 adjacent to the inner wall as are located on the outer periphery of the inner tube, it follows that the cupshaped members adjacent to this inner wall will be much smaller in diameter than those located on the periphery. In Fig. & of the drawings a diagrammatical view is shown which illustrates clearly a section of the inner tube extending in a flat plane and showing the variation in size of the various cup-shaped members.

Between the concavities formed in the outer face of the tube 10 are a plurality of bearing surfaces 14 which are adapted to bear against the inner face of the shoe 15 when the tube 10 is inserted therein.

The tube 10 with the inwardly extending cupshaped members formed therein are constructed to flt the shoes 15 with the bearing surfaces 14; in contact with the inner wall thereof, as shown in Fig. 2 of the drawings.

The curvature of each cup-shaped member is greater than the curvature that said cup-shaped members would assume when the inner tube was inflated and the outer wall of each cup-shaped member pressed into contact with the inner wall of the shoe 15 as shown in Fig. 3 of the drawings.

It is obvious that when the tube 10 with the inwardly extending cup-shaped members formed therein has been inserted into the shoe 15 and the tube inflated, the pressure of the air within said tube will force the material forming the cup-shaped members 11 outwardly into contact with the inner wall of the shoe 15, and in so doing, the material will be compressed sidewise in every direction.

iVhen inflated, the tube assumes the condition shown in Fig. 3 of the drawings, and it is obvious that the tube will assume'this condition when the air contained therein has received its first compression. When the tube 10 has assumed the condition shown in Fig. 3 of the drawings, the air therein is further compressed and the entire inner wall of said tube is subjected to the necessary pressure required to retain the tire inflated and support the weight that must be sustained thereby.

In order to secure the greatest degree of compression of the material when the tube is inflated, in the present invention each side oi every cup-shaped member 11 has a concaved depression 16 formed therein the depth of which gradually decreases from the edge 12 toward the center of the cup-shaped member 11.

As shown in Fig. 6 of the drawings, the dotted line 1'? indicates the continuation of the inner sphericalwall of the cup-shaped member in case no concaved recess 16 is formed therein, this line being drawn to more clearly indicate the shape and depth of the concaved recesses 16.

It will be noted from an inspection of F 4: of the drawings, that on each side of an intersecting edge 12, there is a concaved recess 16, these two abut-ting concaved recesses intersecting each other and forming a deeper concaved edge 13 than the concavity 13 shown and described in said prior patent.

These concaved ridges 13, owing to the intersection of the concaved recesses 16 have a substantially sharp edge as indicated in Fig. v6 of the drawings.

With the form of the inner tube shown and described in the prior patent in use, it was discovered in practice that portions of the inner tube adjacent to the bearing points 14 were not sufficiently compressed in the inflation of the inner tube to effectually pre vent leakage in case the inner tube was punctured at that particular point.

To overcome this objection and provide a means whereby the member forming the tube would be compressed throughout when said tube was inflated, it was found essential to form the concaved radial depressions 16 in each of the cup-shaped members 11.

As before stated, the formation of these con caved depressions 16 caused a greater depth of the concaved'sharp edge 13 so that when the material outside of this sharp edge 13 was forced outwardly upon inflation, there was a great amount of compression of said material at this particular point lengthwise of said edge 13. Moreover, by making the concaved depressions 16 extend from each of the edges 13, a still, greater compressi'on of the material outside of these de pressions would be assured upon the inflation of the tube. As the depressions 16 extend inwardly from each of the sides 13 of the cup-shaped members 11, it is obvious that the compression of the material of the tire upon inflation would be in every direction.

As a result of providing an inner tube with these concaved depressions 16 and the resultant increases in the depth of the concaved edge 13, there is assured, upon the inflation of the inner tube, such compression of the material throughout the entire body thereof as to prevent any leakage from the inner tube should said tube become punctured. i

In case a nail or other member causes a puncture through the shoe 15 and through the inner tube 10', the pressure of the compressed air within the tube 10 will cause the material forming the tube to grip upon the surface of the puncturing member and prevent any escape of the air while said memberis retained in the material of the tube.

Should, however, the puncturing member become dislodged, the pressure of the compressed air within the tube 10 will cause the walls of the puncture to immediately come into contact with each other and thereby prevent any leakage of the air within the tube 10. r

It is self-evident that whenthe tube has been inflated, the material of said tubewill have become compressed sidewise in every direction and the tendency of said material would be to expand, so that if any ordinary sized opening is made through the walls of the tube, the expansion of the material will immediately close the same. 7

This makes a very efiective inner tube for tires of motor cars, inasmuch as any punctures which may be created therein will be self-closing, and the tire trouble now so common will be reduced to a minimum.

It is believed that the many advantages of this invention will be fully understood from from the foregoing description.

Having thus described my invention, I claim 1. An inner tube provided with a plurality of inwardly projecting cup-shaped members each having a plurality of sides, and a concaved depression extending from each side toward the center of said cupshaped member.

2. An inner tube provided with a plurality of inwardly projecting cup-shaped iembers each having a plurality of sides, and a concaved depression extending from each side toward theocenter of said cupshaped member and-gradually decreasing in depth.

3. An inner tube provided with a plurality of inwardly projecting cup-shaped members, the cup-shaped members in the central row being all of the same size while the cup-shaped members on either side of said central row are of gradually decreaslng slze.

4. An inner tube provided with a pluwrality of inwardly projecting cup-shaped members in concentric rows, the cup-shaped members in the inner rows thereof being of smaller size than those in the outer rows.

Signed by me at 7464 Old South Bldg, Boston, Mass, this 29th day of November,

-AI B. SHAW.

Witnesses:

WALTER E. LOMBARD, NATHAN G. LoMBARo. 

